ARM: EXYNOS: SWRESET is needed to boot secondary CPU on exynos3250

Without software reset the secondary CPU does not power up and
exynos_boot_secondary() ends with pen_release equal to 1. This can be
observed in dmesg:
	CPU1: failed to come online
	Brought up 1 CPUs
	SMP: Total of 1 processors activated.
	CPU: All CPU(s) started in SVC mode.

When booting the secondary CPU on Exynos3250 execute also software
reset for core 1.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>